In automotive racing, typically known as "drag racing" two cars line up side-by-side, on a starting line, with each car in a track lane. A series of starting lights are mounted on a "Christmas tree" which are illuminated sequentially and count down until a green light appears. The illumination of the green light signals the start of a race. The racers take off on the starting line and then race to the end of the track which consists of a straight two lane road, usually up to one-quarter mile in length. The object is to get the cars to accelerate as quickly as possible so as to be the first one to cross the finish line. The elements that comprise a winning race is the combination of the time it takes for a car to run the length of the race course plus the amount of time it takes for the driver to react to the starting lights.
The series of lights, called a "Christmas tree" is located in the center of the two lanes between the two race cars near the starting line. The "Christmas tree" contains a number of lights which typically consists of a pre-stage light, a stage light, a series of count down lights, which number from 1 to 5 amber lights, and then finally a green light. A red light is also provided for each lane and is illuminated when there is a foul. The pre-stage lights indicate to the driver that the driver is near the starting line and the stage lights tell the driver that the driver is actually on the starting line.
A building located near the starting line, called the timing tower, contains an electronic control box which times the race cars and also controls the Christmas tree. When the track official who is located at the starting line activates a switch that signals the electronic control box, the electronic control box starts a count down sequence on the Christmas tree of the count down lights, i.e. amber lights, in a precisely timed pattern eventually ending up with the green light at the end of sequence. The racers may drive away from the starting line any time after the racer's respective green light comes on. If the racer activates too soon, a foul start or a red light is indicated, meaning that the driver is disqualified from the race. To start the car moving, the driver either releases the brakes on the car or releases a switch that allows the car to take off from the starting line. Clearly, the optimal starting moment is to have the car leave the starting line at exactly the instant that the green light is activated.
Since starting time is so critical, electronic practice aids known as practice Christmas trees are known from the prior art. These practice Christmas trees are either full size Christmas trees or are miniature versions thereof which flash the count down lights. The user reacts to the green light by activating a switch, like the switch that starts a car. The device measures the response time, typically known as "reaction time" and then displays the time in some sort of digital readout. The closer to the race track conditions, the more realistic the training exercise would be. With better timing, better results would occur in terms of winning at the race track.
One shortcoming of the prior art practice Christmas tree is the absence of sound and/or noise simulating race track conditions. Race cars create loud and distinctive sounds compared to passenger cars and this can be distracting to many drivers. However, it is not desirable, for a driver to avoid the distraction of the engine noises by, for example, wearing ear plugs at the race track so that the race track conditions are closer to the practice conditions. This is not a viable solution for a number of reasons. The most important reason is that the exhaust sounds of an engine are so loud that the ear plugs muffle the noise but do not silence it. In addition, as part of a successful racing program, it is essential for the driver to provide feedback to the mechanics on the performance of the engine as detected by the noise. The driver does this by listening to the engine, drive train and the car itself as the run is made. This helps the driver and the mechanic diagnose performance related problems. Muffling the sound as the driver initiates racing conditions would be detrimental to the racing program.
In some forms of drag racing, the electronic control box, located in the timing tower, delays the start of the count down lights on one side of the Christmas tree, so that one of the drivers is given a "handicap". The handicap consists of a certain amount of time by which the slower car is permitted to leave the starting line. This control box is programmed with the respective elapsed time expected for each car which then determines the amount of handicap (the difference between the elapsed times) by which the slower car is allowed to leave before the faster car.
Because the reaction time of a driver to activate the switch that starts a vehicle, is so critical to the performance in starting a vehicle, in the prior art, delay boxes, such as that disclosed in U.S. Pat. No. 4,467,219, are well known. A driver inputs an amount of reaction delay time into the delay box. The user would activate the switch on the delay box immediately upon perceiving the occurrence of the first of the plurality of count down lights indicating a count down to the green light. The delay box would count down based upon the amount of delay time inputted by the driver, and upon the end of the delay time period, the vehicle would be started. The amount of reaction delay time inputted by the driver into the delay box would equal the amount of time normally attendant to the count down of the lights, and the reaction of the driver in activating the switch on the delay box. Thus, a driver can program the delay box to start a vehicle more consistently.
Finally, in the prior art, it is known to provide a cross-over delay box. With a cross-over delay box, the driver of a faster vehicle ("faster driver") at a race track can program each car's expected elapsed time and also program the amount of reaction time delay of the faster driver. Thus, a faster driver would typically initiate the cross-over delay box as soon as the faster driver sees the slower driver's first amber light illuminated. The cross-over delay box would compute the amount of time that is attributable to the handicap and the reaction time delay of the faster driver activating the cross-over delay box thereby releasing the engine brakes hopefully at the same time as the green light of the faster driver is illuminated. Although cross-over delay boxes are know and have been used at races, they have not been incorporated or used in a practice Christmas tree device.